Ross Ridge wrote: t formal definition.
Most of GCC's long list of extensions to C are also implemented as extensions to C++, so you've already lost this battle in GNU C++.
And many of them are ill-defined (and some would agree ill-considered). Mistakes in the past are not a good reason for mistakes in the future.
Trying to add new a new feature without an existing implementation only makes it harder to get both a correct formal definition and something that people will actually want to use.
I think the best procedure is to discuss new features from a language design point of view, and the committee is the best forum for that, then implement them as *part* of the (typically fairly drawn out) process of adding a new feature.
